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Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Andromeda Galaxy: 05-14 (4), 05-15 (4), 05-16 (4), 05-10 (3), 05-11 (3) — by astronomy; check the weather when the night is within four days.
2033-04-17astronomy score per night — click a bar for that night2033-05-16
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2033-04-17 Sun 0 — unknown — 89.5° 12:20 7.16 91% 130.2°
2033-04-18 Mon 0 — unknown — 89.6° 12:20 7.1 84% 121.1°
2033-04-19 Tue 0 — unknown — 89.7° 12:15 7.04 76% 111.1°
2033-04-20 Wed 0 — unknown — 89.7° 12:10 6.99 67% 100.5°
2033-04-21 Thu 0 — unknown — 89.6° 12:05 6.93 56% 89.4°
2033-04-22 Fri 0 — unknown — 89.7° 12:00 6.87 45% 78.1°
2033-04-23 Sat 0 — unknown — 89.8° 11:55 6.81 34% 66.8°
2033-04-24 Sun 0 — unknown — 89.7° 11:50 6.75 24% 55.8°
2033-04-25 Mon 0 — unknown — 89.6° 11:45 6.69 14% 45.7°
2033-04-26 Tue 1 — unknown — 89.6° 11:45 6.64 7% 37.7°
2033-04-27 Wed 1 — unknown — 89.7° 11:40 6.58 2% 33.9°
2033-04-28 Thu 1 — unknown — 89.8° 11:35 6.52 0% 35.7°
2033-04-29 Fri 1 — unknown — 89.7° 11:30 6.46 1% 42.1°
2033-04-30 Sat 1 — unknown — 89.5° 11:25 6.4 5% 51.4°
2033-05-01 Sun 1 — unknown — 89.6° 11:25 6.35 11% 61.8°
2033-05-02 Mon 1 — unknown — 89.7° 11:20 6.29 18% 72.6°
2033-05-03 Tue 1 — unknown — 89.7° 11:15 6.23 27% 83.4°
2033-05-04 Wed 1 — unknown — 89.6° 11:10 6.17 37% 94.0°
2033-05-05 Thu 2 — unknown — 89.5° 11:10 6.12 46% 104.3°
2033-05-06 Fri 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.7° 11:05 6.06 56% 114.1°
2033-05-07 Sat 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.8° 11:00 6.0 66% 123.3°
2033-05-08 Sun 2 — unknown 04:50–05:00 (marginal, 0.17 h) 89.7° 10:55 5.95 74% 131.7°
2033-05-09 Mon 2 — unknown 04:50–05:00 (marginal, 0.17 h) 89.6° 10:50 5.89 82% 138.9°
2033-05-10 Tue 3 — unknown 04:45–05:00 (marginal, 0.25 h) 89.5° 10:50 5.83 89% 144.0°
2033-05-11 Wed 3 — unknown 04:05–04:15 (marginal, 0.17 h) 89.7° 10:45 5.78 94% 146.2°
2033-05-12 Thu 3 — unknown 04:45–04:55 (marginal, 0.17 h) 89.8° 10:40 5.72 98% 144.6°
2033-05-13 Fri 3 — unknown 04:00–04:10 (marginal, 0.17 h) 89.7° 10:35 5.67 100% 139.8°
2033-05-14 Sat 4 — unknown 03:55–04:10 (marginal, 0.25 h) 89.5° 10:30 5.62 100% 132.4°
2033-05-15 Sun 4 — unknown 03:50–04:05 (marginal, 0.25 h) 89.6° 10:30 5.56 98% 123.5°
2033-05-16 Mon 4 — unknown 03:45–04:05 (marginal, 0.33 h) 89.7° 10:25 5.51 94% 113.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-04-17&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.